Existing technologies such as x-ray imaging systems have been used to investigate the internal structure and properties of a range of objects including food products and the human body. However, systems employing X-rays (or other ionizing radiation) suffer from a range of health and safety concerns. Ionizing radiation is known to be capable of causing damage to tissue and other materials. Consequently, equipment employing x-ray radiation must be provided with sufficient screening to ensure operating and other personnel are not exposed to the radiation.
In addition, the size of an x-ray system is large, and consequently not appropriate in certain manufacturing situations. A further drawback of X-ray systems is the relatively high cost of an X-ray imaging system.
Terahertz imaging systems have also been employed for imaging an internal structure of an article. However, imaging water-containing samples using these systems is challenging due to the high attenuation of terahertz frequency signals by water molecules.